PORTS OF CALL
An obscure series from 1935 or 1936 in which each episode deals with a voyage to a different country where events of that country's history are dramatized. They each begin with the low moan of a tramp steamer's whistle and the announcement of the series title, followed by a musical interlude.
From the Old Time Radio Researcher's Group. See "Note" Section below for more information on the OTRR.